Recently, methicillin resistant Staphylococcus aureus (hereinafter designates as MRSA) has become a social problem as a major causative microorganism of hospital-acquired infection. This pathogenic microorganism is resistant to various medicines such as β-lactam antibiotic, and antibiotics such as glycopeptide antibiotic vancomycin and aminoglycoside antibiotic arbekacin, which are reported at present to exhibit almost no resistance, are generally used for treatment of MRSA. In addition to this, combination therapy of β-lactam antibiotics or that of β-lactam antibiotic and other antibiotic having different active site is employed at present (Yoshimi Hasegawa et al. “Science of antibiotic administration”, p. 264-273, 1998).